As described in US Patent Application Publication No. US2011/0056712 by Rozendaal et al, in one known form of conservation tillage, the soil is minimally disturbed prior to planting in order to allow air to penetrate the mat of crop residue. This technique is variously known as minimum tillage, residue management, soil aeration or seedbed aeration. A farm implement, sometimes known as a vertical tillage implement, is used to cut the crop residue and penetrate a short distance into the surface of the soil while lifting the soil vertically to permit access of air to the soil.
Known constructions of coulter disk vertical tillage implement typically support the coulter disk by an exposed spring member to resiliently bias the coulter disk downwardly into engagement with the ground. The exposed configuration of the spring member however commonly results in considerable debris being trapped in the spring such as corn stalks and the like which is a nuisance and can affect performance of the implement. Another deficiency which known constructions of vertical tillage implements having adjustable toolbar sections is the limited downforce that can be applied to the coulter disks due to the difficulty in providing adequate support to the toolbar sections supporting the coulter disks thereon when the toolbar sections are adjustable in angular orientation. Yet another deficiency with known constructions of vertical tillage implements is the cumbersome manner of replacing the coulter disks if damaged.